1. Technical Field
The present, invention relates to video technology and more specifically to technologies of combining images in virtual reality (VR) settings.
2. Discussion of Prior Art
Visual environment simulation computers develop graphical data into images which can be displayed as views of virtual reality environments. VR capabilities may be useful in various real world situations. Ordinary visible objects and surroundings can, through the: intermediary of head-up displays, become subjects of reconceptualizations in virtual worlds created by computers.
It has not always been feasible to superpose VR images on physical world settings. Typically, in order not to obscure physical environments, they are viewed through semi-transparent or beam-splitter visors, combining simulation images for display.
U.S. Pat. No. 4,398,799 by Swift discloses a head-up display in which a cathode ray tube (CRT) projects video images onto a stationary semi-reflecting visor, combined with the physical world view, into the eyes of a user. Reflected images intersect a head.-mounted second semi-reflector and are reflected into a video camera mounted on the user's head, but the camera is not needed for the composite view to be seen by the user.
U.S. Pat. No. 5,151,722 by Massof et al. discloses a video display which is held in a user's line-of-sight. A head-side mounted video source projects images through folding optics into the line-of-sight of the user. The video source can include a video camera which is offset and incurs parallax error.
Combining images by overlaying simulation video pixels on semi-reflective visors compromises the light from both real world and simulation sources, which interferes with presenting either of them completely. Physical environment light penetrating visors is not completely blocked by simulation video pixels.
U.S. Pat. No. 5,035,474 by Moss et al. criticizes semi-transparent visors for reducing the light available from physical world sources. A visor's positions on a user's head are tracked and replicated by an infra-red camera which is offset mounted and incurs parallax error. The user has restricted mobility.
Physical and virtual environment views must be from identical points of view in order to be correlated without incurring parallax error. A visor mounted on a user's head where its position is tracked and replicated by a servo mechanism should, ideally, be on-axis, but should not obscure the user's view of the physical world. Preserving physical environment views conflicts with both goals of complete control by simulation video pixels and also with aligning a (non-semireflective) servo co-axially with the user's line-of-sight to avoid parallax error. Yet both of these goals are important for precise interaction between simulated and physical environments.
In other prior art, U.S. Pat. No. 4,496,981 by Ota economizes materials and processing through consolidating video camera sensor and display cell functions, as shown by FIG. 1.